LibGfx: Prepare the paint code for fonts whose glyphs are color bitmaps

This patch does three things:
- Font::has_color_bitmaps() (true if CBLC and CBDT are present)
- Glyph now knows when its bitmap comes from a color bitmap font
- Painter draws color bitmap glyphs with the appropriate scaling etc

Userland/Libraries/LibGfx/Font/VectorFont.h

@@ -47,6 +47,7 @@ public:
     virtual u16 width() const = 0;
     virtual u8 slope() const = 0;
     virtual bool is_fixed_width() const = 0;
+    virtual bool has_color_bitmaps() const = 0;
 };
 
 }